Corneal thickness not associated with eye length, study shows

Thin corneas are not associated with long eyes, a study found. Central corneal thickness and axial length are independent occurrences and have no statistical association with each other, according to the study authors.

Mitsugu Shimmyo, MD, and Paul Orloff, MD, of the Manhattan Eye, Ear and Throat Hospital, performed the study to investigate whether a thin cornea, which has been identified as a risk factor for glaucoma, might be associated with a weak sclera, an anatomic trait that might contribute to the vulnerability of the lamina cribrosa.

The researchers reviewed the charts of 1,084 eyes of 546 patients to determine correlations between central corneal thickness and axial length. The mean age of the patients was 66 years, ranging from 9 to 93 years. The review included 540 eyes of Hispanic patients, 215 eyes of Asian patients, 212 eyes of white patients and 117 eyes of black patients. Fewer than 10% of the eyes had glaucoma. All the eyes had central corneal thicknesses and axial length measured by ultrasonic pachymetry.

The mean central corneal thickness of all eyes was 543.1 µm, and the mean axial length was 23.44 mm.

The total patient study group showed no statistically significant association between central corneal thickness and axial length. A subgroup analysis by age, gender and race also failed to support an associative relationship.

The study is published as a brief report in the March issue of American Journal of Ophthalmology.